#define  _CRT_SECURE_NO_WARNINGS 1
#include<stdio.h>
#include<string.h>
#include<assert.h>
//int my_strcmp(const char* p1, const char* p2)
//{
//	assert(p1 != NULL);
//	assert(p2 != NULL);
//	while (*p1 == *p2)
//	{
//		if (*p1 == '\0')
//			return 0;
//		p1++;
//		p2++;
//	}
//	return *p1 - *p2;
//}

char* my_strstr(const char* str, const char* str2)
{
	char* cp;
	char* s1; 
	char* s2;
	if (str == NULL)
	
		return (char*)str;
		while (*cp)
		{
			s1 = cp;
			s2 = (char*)str2;
			while (*s1 && *s2 && !*s2 - *s1)
			{
				s1++;
				s2++;
			}
			if (*s2 == 0)
				return(cp);
			cp++;
		}
		return NULL;
}